Diodes Incorporated APR34309CAMPTR-G1

Overview

APR34309CAMPTR-G1 from Diodes Incorporated is a secondary-side synchronous rectification (SR) Combo IC integrating an N-channel MOSFET and driver for DCM-mode flyback converters. It features 8 mΩ R_DS(ON), 20 A continuous drain current, and output voltage detect functionality for primary-side control coordination. Designed for 5 V output adapters and chargers, it reduces secondary-side conduction loss by replacing Schottky diodes with active MOSFET switching.

For engineers reviewing the APR34309CAMPTR-G1 datasheet, APR34309CAMPTR-G1 pinout, APR34309CAMPTR-G1 application, or APR34309CAMPTR-G1 equivalent, key selection criteria include SR turn-on/turn-off thresholds (V_THON = 0 V, V_THOFF = −10 mV), minimum on-time control (1.8 μs at 25 V·μs), dynamic OVP discharge timing (t_{OVP_LAST} = 2.0 ms), and SO-8EP thermal performance (θ_JA = 56 °C/W).

Technical Context

The APR34309CAMPTR-G1 implements volt-second product detection via the AREF pin to reject resonant ringing interference during DCM flyback operation. Its internal comparator monitors V_DET–V_CC to trigger gate drive only when the integrated area exceeds K_qs × R_AREF, ensuring reliable SR activation without false triggering.

It embeds dual protection functions: periodic V_CC monitoring with t_DIS = 30 ms discharge enablement at V_DIS = 5.3 V, and fast OVP response with IOVP = 40–100 mA discharge current activated at VOVP = 5.74 V and sustained for t_{OVP_LAST} = 2.0 ms.

Key Specifications

Pinout & Package

APR34309CAMPTR-G1 is housed in a thermally enhanced SO-8EP package with exposed drain pad (EP) for low-thermal-resistance mounting. The 8-pin layout includes three GND pins (6, 7, 8) tied to MOSFET source and a dedicated DRAIN pin (5) connected to the exposed EP for high-current path routing.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous rectification applications.

Compared with APR34308CAMPTR-G1, APR34309CAMPTR-G1 adds integrated OVP discharge and superior ringing immunity-critical for unregulated adapter designs. Against MP6908AGS-Z, its −10 mV V_THOFF and volt-second blanking deliver more robust DCM timing in variable-load, high-noise environments.

Availability

APR34309CAMPTR-G1 is available at Aetrix Electronics and suitable for USB-C adapters, DSL modem power modules, wireless charging transmitters, and industrial auxiliary supplies requiring stable component supply with full RoHS/Green compliance and traceable sourcing.

Supply support for APR34309CAMPTR-G1 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in power management, signal integrity, and protection solutions for consumer, industrial, and communications markets.

The APR34309CAMPTR-G1 belongs to Diodes' secondary-side synchronous rectification controller product line, designed specifically for high-efficiency, low-noise DCM flyback converters in compact AC/DC adapters and auxiliary power supplies.

FAQ

What is the purpose of the AREF pin and how is its resistor value determined?

The AREF pin sets the volt-second product threshold for synchronous rectifier activation using an external resistor to GND. Its value is calculated as R_AREF = Area2 / K_qs, where Area2 is the target integration threshold between ringing (Area3) and true DCM conduction (Area1). For worst-case primary peak current, R_AREF is typically 10–22 kΩ with 20 nF CAREF capacitor to stabilize the threshold against noise.

How does the APR34309CAMPTR-G1 handle resonant ringing during DCM operation?

It uses volt-second product detection: the internal integrator only triggers SR drive when (V_DET−V_CC)×t_ONP exceeds a programmable threshold (e.g., 25 V·μs). Ringing waveforms produce smaller volt-second areas than true DCM conduction events, so they are rejected-eliminating false turn-on without requiring complex external filtering.

What is the role of the VDET pin beyond synchronous rectification sensing?

VDET serves dual functions: it provides drain-voltage sensing for SR timing and outputs periodic pulses during UVLO recovery or OVP discharge cycles. When V_CC drops below V_OFF or rises above V_DIS, VDET asserts a pulse train with t_OSC = 30 μs period-enabling primary-side controllers to detect secondary-side fault conditions and adjust switching behavior accordingly.

Can the APR34309CAMPTR-G1 be used in CCM flyback topologies?

No-it is explicitly designed for DCM operation only. Its volt-second detection mechanism, minimum on-time blanking (t_{LEB_L}), and −10 mV V_THOFF threshold rely on the zero-current crossing signature of DCM. In CCM, continuous secondary current prevents reliable V_DS zero-crossing detection, leading to erratic SR timing and potential shoot-through risk.